Method and apparatus for fabricating curved structural beams



J- R- TABOR April 20, 1965 METHOD AND APPARATUS FOR FABRICATING CURVED STRUCTURAL BEAMS 2 Sheets-Sheet 1 INVENTOR fill 16 7250? lrraavzy Filed Aug.

United States Patent 3,178,922 METHOD AND APPARATUS FOR FABRICATING CURVE!) STRUCTURAL BEAMS John R. Tabor, 3801 Carter St., Racine, Wis. Filed Aug. 8, 1962, Ser. No. 215,696 8 Claims. (Cl. 72-152) This invention relates to method and apparatus for fabricating curved structural beams.

Curved structural beams, typically of the type used to support tunnel tube walls, are conventionally fabricated by bending straight structural beams into their desired curved shape. Prior art techniques known to me simply involve bulldozing the beams into the approximate desired shape. Stresses are thus introduced which tend to warp or twist the beam. Beams thus shaped are inaccurate and may not hold their shape permanently because of the unrelieved stresses produced by the bulldozing operation.

The apparatus and method of the present invention fabricates curved structural beams in an efficient and inexpensive manner, which is characterized by cold working at least a portion of the beam after it has been bent, thus to relieve bending stresses and to set or iron the bend in place. Curved beams fabricated according to the present invention will hold their shape permanently.

The structural beams with which the present invention is concerned have relatively large cross sections. Accordingly, when bent into curved shape, the outermost peripheral portions thereof are stretched. The metals of most structural beams are relatively elastic and there is a tendency for the elasticity of the stretched member to tend to return the bent member towards its original shape or to warp or twist the beam. The cold Working operation herein performed on the outermost flange of the structural beam relieves such stresses, elastic forces, etc., so that the ultimate bent shape of the beam is relatively permanent.

Other features, objects and advantages of the invention will appear from the following disclosure, in which:

FIG. 1 is a plan view of apparatus embodying the invention.

FIG. 2 is a side view thereof, taken along the line 22 of FIG. 1.

FIG. 3 is a fragmentary cross section thereof, taken along the line 3-3 of FIG. 1.

FIG. 4 is a detailed view of an optionally usable beam web support mechanism.

FIG. 5 is a side elevation of the mechanism shown in FIG. 4.

FIG. 6 is an enlarged fragmentary cross section taken along the line 6--6 of FIG. 1.

FIG. 7 is an enlarged fragmentary section taken through an optionally usable outermost flange back up roller set.

FIG. 8 is a perspective view of an H-beam bent into curved shape according to the method and apparatus of the present invention.

Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto.

"ice

The apparatus is desirably mounted for stability upon a concrete or like foundation base 12, which provides a seat for pintle 13 on which the rotary former 14 turns. The former may consist essentially of a wheel with its periphery shaped to the desired curve of the beam, for example, circular. Wheel 14 has a beam seat 15 recessed within channel forming flanges 16 between which the beam 17 is embraced. For purposes of illustration, beam 17 is H-shaped in cross section, although other conventionally shaped beams may be formed according to the invention.

The wheel 14 has a drum 18 about which a draw cable 19 is wound. Cable 19 is connected to the piston 26 of a single acting hydraulic motor 21. As indicated in FIG. 2, the motor 21 is desirably mounted on an inclined base 24 to lie below the turning plane of the rotary former 14.

The rim of the former is provided with a coupling 25 which includes an eccentrically mounted clamp shoe 26 adapted to engage one end of the straight H-beam 17. To emplace the beam 17, it is initially threaded between the former and a guide wheel 44 and into the coupling 25. As indicated in FIGS. 3 and 6, the H-beam 17 has an outside flange 27, an inside flange 28, and a transverse interconnecting web 29. The inside flange 28 fits against the seat 15 of the forming wheel 14 and the edges of the flanges 27, 28 are embraced by the flanges 16 on the former 14, thus to hold the beam in position.

Beyond the point of tangency 32 between the beam 17 and the forming wheel 14, a cold working tool, such as the disclosed serrated roller 33, is mounted to contact the outer face of the outer flange 27 of the H-beam 17. The serrations on roll 33 may consist simply of parallel teeth or ribs, or the roll surface may be otherwise roughened or knurled. Roller 33 is supported in a caster-action mounting 34 which includes a trail arm clevis 35 which is swingably mounted on the base 12 on pin 36 and a pressure arm clevis 37 mounted on the piston 38 of a hydraulic motor 39 which is pivotally connected to the base 12 on pin 42. The respective clevises are mutually pivotally connected to roll 33 by pin 43. By reason of the caster action mount aforesaid, the serrated roll 33 is free for limited movement about the axes defined by pins 36, 42 and 43 and the roll 33 will properly track or trail in the path of the beam 17 as it is wrapped around the forming wheel 14.

Hydraulic motor 39 is capable of applying great pressure against the serrated roll 33 and the outer flange 27 of the H-beam 17. In practice, hydraulic motor 39 is capable of exerting up to fifty tons of pressure on the roller.

In operation, the H-beam 17 is clamped to the coupling 25. The backup or guide roller 44 mounted on base 12 on pin 45 holds the straight or unbent portion of the beam 17 on an approach path of tangency with respect to the forming wheel 14. Wheel 14 is turned in the direction of arrow 41 by reason of the hydraulic motor drawing in on the cable 19. The H-beam 17 will accordingly be bent at its point of tangency 32 with the forming wheel 14.

In the course of bending the beam as aforesaid, its outer flange 27 will be stretched. This stretching operation sets up elastic and other stresses within the metal. Beyond the point 32 where the beam is initially bent, and at the point 46 where the trailing roller 33 contacts the beam flange 27, stretched outer flange 27 is cold worked by the serrated or otherwise roughened roller 33 in order to iron out or relieve the stresses induced in the beam initially by bending it at the point 32. As indicated in FIG. 8, the outer flange 27 has produced in it the markings 47 formed therein by the cold working action of the roller 33. In this manner, the curve produced in th H-beam 17 is set by cold working its stretched outer flange to relieve stresses. Accordingly, after the beam has been bent to its desired shape and released from the forming wheel 14, the curved shape will remain permanently fixed without any substantial tendency for the beam to distort therefrom.

Pending the next operation the pressure in hydraulic motor 21 is relieved and the wheel 14 is returned to initial position by rotating it against the direction of arrow 41 by motor 50 which draws cable 51 which is Wound on sheeve 60 on wheel 14.

The precise amount of the offset of the pressure point 46 from the point of tangency 32 is not particularly critical, the importance of the offset being measured in terms of cold working the stretched outer flange after bending has occurred therein. In a practical embodiment of the invention, the angular displacement of point 46 from point 32 is approximately eight degrees circumferentially about the periphery of the turning wheel 14. This is also an advantageous location for the roll 33 as the bent beam tends to bulge at this point.

An optional modification of or addition to the apparatus aforedescribed is shown in FIG. 7. In this instance, the forming wheel 14 may be provided with a very shallow seat 49, the greater portion of the flanges 16 of the embodiment previously described being omitted here to provide room for supporting backup rollers 48 within the channel of the Habeam 117. These rollers are pivotally mounted on arms 48, which, in turn, are pivotally mounted on the pin 43 aforesaid. The rollers 48 are desirably serrated or otherwise knurled, etc., as is roller 33, thus to cold work the inside of the outer beam flange 27. Rollers 48 also function to preclude inward 1.

bending of the flange 27 under pressure of roll 33.

Another optionally usable attachment is shown in FIGS. 3, 4 and 5. Trailing web support mechanism is provided to trail from bracket 55. The mechanism comprise-s two frames 54, one for each side of the beam web 29. Each frame 54 has rollers 52 which bear on opposite sides of the web 29 to preclude any tendency of the web to buckle under pressure of the ironing roller 33. Rollers 52 in each frame 54 include roller 52a,

which is movably mounted on a slidable sub-frame 53 mounted within the frame '4, and fixed roller 52b stationarily mounted on the frame 54.

To force rollers 5 2a and 52b under pres-sure against the web 29, subframe 53 for roller 52a is mounted for sliding movement longitudinally of the frame 54 under pressure of the double acting hydraulic motor 56. Motor 56 has a piston 57 pivotally connected on the pin 58 to arms of the sub-frame 53. Roller 52a is pivotally connected on pin 59 to the arms of the sub-frame 53. A reaction roller 62 is also mounted on the subframe arms 53 on pin 63.

Pins 55 and 59 also extend through longitudinal slots 64, 65 in the frame 54, thus to permit relative movement of the subaframe 53 with respect to the main frame 54. Pin 63 for reaction roller 62,, however, rides in inclined slots 66 formed in the main frame 54. Accordingly, when the subframe 53 is forced to the right, as shown in FIGS. 4 and 5, under pressure of the hydraulic motor 56, reaction roller 63 is forced upwardly against the appropriate channel flange 16 of the former wheel 14 to press the wheels 52a, 52b against the web 29. Inasmuch as the frames 54- are provided on each side of the web 2d and the hydraulic motors 56 of each are interconnected for concurrent operation, the web 29 will be under centering pressure from the wheels 52a, 52b to preclude it buckling of the web 55* during the bending operation and during the cold working of the flange 27 under pressure of roll 33.

I claim:

1. Apparatus for fabricating a curved H-beam from a straight H-beam, said beam having side flanges and a transverse Web, said apparatus comp-rising:

(a) a rotary former having a rim providing a seat for one of said beam flanges,

(11) means for mounting a beam tangentially against said rim,

(0) means for wrapping the beam about said former to bend said beam at its point of tangency with said rim and pursuant to which the other beam flange is stretched during bending,

(d) a cold working roll,

(e) means for mounting said roll in contact with the outer surface of the other beam flange and offset beyond said point of tangency,

(f) motor means for pressing said roll against the outer surface of said other beam flange with sufficient force to cold work said other beam flange after the bending and stretching thereof.

2. The apparatus of claim 1 in which said means for 25 mounting said roll comprises a caster mount for tracking of the roll with respect to the beam.

3. Apparatus for fabricating a curved structural beam from .a straight beam, said apparatus comprising:

a curved former having a rim,

means for mounting a beam tangentially against said former rim,

means for wrapping the beam about said former to bend said beam at its point of tangency with said rim and pursuant to which portions of the beam are stretched during bending,

and means offset beyond said point of tangency to cold work stretched portions of said beam after the bending thereof.

4. The apparatus of claim 3 in which the means for cold working the beam comprises a roughened roll and a motor to press said roll against said beam to roughen the beam surface exposed to the pressure of the roll.

5. The apparatus of claim 4 in which said roll is provided with a caster mount to track the roll with respect to the beam.

6. Apparatus for fabricating a curved structural beam from a straight beam, said apparatus comprising:

a curved rotary former having a rim,

means for mounting a beam tangentially against said former rim,

means for rotating said former to bend said beam at its point of tangency with said rim and pursuant to which portions of the beam are stretched during bending,

a roll offset beyond said point of tangency and engaged with said beam,

and a motor to press said roll against the beam to cold work stretched portions of the beam exposed to the roll after the bending thereof.

7. Apparatus for fabricating a curved beam from a straight beam, said beam having side flanges and a trans verse web, said apparatus comprising:

(a) a rotary former having a rim providing a seat for one of the beam flanges,

(b) afirst roll,

(c) means for mounting said first roll in contact with the outer surface of the other beam flange,

(d) motor means for pressing said first roll against the outer surface of said other beam flange with sufllcient force to cold work said other beam flange,

(e) a second roll,

(f) and means for mounting said second roll at the inner surface of said other beam flange to support said other beam flange against the pressure of the motor means.

8. Apparatus for fabricating a curved beam from a straight beam, said beam having side flanges and a transverse web, said apparatus comprising:

(a) a rotary former having a rim providing a seat for one of the beam flanges,

(b) a first roll,

(0) means for mounting said first roll in contact with the outer surface of the other beam flange,

(d) motor means for pressing said first r011 against the outer surface of said other beam flange with suflicient force to cold work said other beam flange,

(e) and roll means at opposite sides of the beam web to support the web against buckling in the course of bending said beam around the former.

References Cited by the Examiner UNITED STATES PATENTS RICHARD H. EANES, Primary Examiner. 

1. APPARATUS FOR FABRICATING A CURVED H-BEAM FROM A STRAIGHT H-BEAM, SAID BEAM HAVING SIDE FLANGES AND A TRANSVERSE WEB, SAID APPARATUS COMPRISING: (A) A ROTARY FORMER HAVING A RIM PROVIDING A SEAT FOR ONE OF SAID BEAM FLANGES, (B) MEANS FOR MOUNTING A BEAM TANGENTIALLY AGAINST SAID RIM, (C) MEANS FOR WRAPPING THE BEAM ABOUT SAID FORMER TO BEND SAID BEAM AT ITS POINT OF TANGENCY WITH SAID RIM AND PURSANT TO WHICH THE OTHER BEAM FLANGE IS STRETCHED DURING BENDING, (D) A COLD WORKING ROLL, (E) MEANS FOR MOUNTING SAID ROLL IN CONTACT WITH THE OUTER SURFACE OF THE OTHER BEAM FLANGE AND OFFSET BEYOND SAID POINT OF TANGENCY, (F) MOTOR MEANS FOR PRESSING SAID RILL AGAINST THE OUTER SURFACE OF SAID OTHER BEAM FLANGE WITH SUFFICIENT FORCE TO COLD WORK SAID OTHER BEAM FLANGE AFTER THE BENDING AND STRETCHING THEREOF. 